Pokemon Collection is, as its name suggests, an incredible collection of some of the best Pokemon classics which are ready to be played at any time. The best part is that you don't even have to download an emulator or their corresponding files. You can play anything from Pokemon Sapphire, Pokemon Ruby, Pokemon Fire Red, Pokemon Leaf Green, and Pokemon Emerald without going through the hassle of looking for a file that's compatible with your current emulator.
All you have to do is download Pokemon Collection, choose the adventure you want to enjoy and start your round as you normally would with any Nintendo.
With Pokemon Collection, and regardless of the version that you play, you can save your progress and continue your round later on hassle-free. Enjoy all the features it offers with no limit restrictions.
On the other hand, and keeping the technical aspects in mind, you can modify the buttons (to make them more or less opaque) by accessing the options tab. Beyond that, just enjoy any of the available Pokemon versions.